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Hi everybody,
I've been given the following assignment: I have to develop a basic graphics packager, by using a Shape class hierarchy, I have to limit my self to 2D shapes (simple one's). The program should interact with the user, the user should specify the position, size, shape and fill characters for drawing the object. Each class has its own draw member functions.
O.K., so I want to go on things easy step by step, so I deceided to write on myself a drive program for testing purposes, which looks like this.
<br />
#include<iostream.h><br />
<br />
class Shape {<br />
protected:<br />
char *figType;<br />
public:<br />
Shape(char *ft = "Define Figure"):figType(ft) {<br />
cout<<"Shape Construct"<<endl;<br />
};<br />
char *getType() {return figType;};<br />
virtual double Area() {return 0.0;};
};<br />
<br />
class Square:public Shape {<br />
protected:<br />
double length;<br />
public:<br />
Square(double l):Shape("Square") {<br />
length = l;<br />
cout<<"A Rectangle Object Created"<<endl;<br />
};<br />
double Area() {return length*length;};<br />
};<br />
<br />
class Rectangle:public Shape {<br />
protected:<br />
double height, width;<br />
public:<br />
Rectangle(double h, double w):Shape("Rectangle") {<br />
height = h;<br />
width = w;<br />
cout<<"A Rectangle Object Created"<<endl;<br />
};<br />
double Area() {return height*width;};<br />
};<br />
<br />
class Triangle:public Shape {<br />
protected:<br />
double height, base;<br />
public:<br />
Triangle(double h, double b):Shape("Triangle") {<br />
height = h;<br />
base = b;<br />
cout<<"A Triangle Object Created"<<endl;<br />
};<br />
double Area() {return height*base;};<br />
};<br />
<br />
class Circle:public Shape {<br />
protected:<br />
double pir;<br />
public:<br />
Circle(double p):Shape("Circle") {<br />
pir = p;<br />
cout<<"A Circle Object Created"<<endl;<br />
};<br />
double Area() {return pir*pir;};<br />
};<br />
<br />
void main() {<br />
Shape *s1;<br />
Rectangle *rp1;<br />
Rectangle r1(3,5);<br />
<br />
s1=&r1;
rp1=&r1;
<br />
cout<<"Area() applied through Rectangle pointer "<<rp1->Area()<<endl;<br />
cout<<"Area() applied through Shape pointer "<<s1->Area()<<endl;<br />
};<br />
All I want to know right now is, how similar is the code to the question asked above ?  Can I apply this structure for using OpenGL instead of using characters for drawing the objects ? And where can I get nice and easy examples ?
Thanks in advance
Tolga
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What you have here is more of a Class FrameWork to support what you've mentioned.
If you try to seperate the problems, you need:
1. A Class FrameWork to declare and support your Shapes. This you seem to have.
2. Something that will allow you to perform drawing of such object.
What I suggest is that you find yourself a simple MFC application that shows how to draw rectangles, elipses, etc onto a window using MFC's CDC.
Then what you'll have left is to connect the two. Each Shape's Draw() method will receive a CDC* variable , which it will use to draw itself onto (using CDC calls).
Here's CDC's documentation over at MSDN
What's most important is that you find a simple MC framework, which I bet you can find on CodeProject.
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Thank you very much, that's what I needed for a start
Tolga
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Hi everybody,
I've been given the following assignment: I have to develop a basic graphics packager, by using a Shape class hierarchy, I have to limit my self to 2D shapes (simple one's). The program should interact with the user, the user should specify the position, size, shape and fill characters for drawing the object. Each class has its own draw member functions.
O.K., so I want to go on things easy step by step, so I deceided to write on myself a drive program for testing purposes, which looks like this.
<br />
#include<iostream.h><br />
<br />
class Shape {<br />
protected:<br />
char *figType;<br />
public:<br />
Shape(char *ft = "Define Figure"):figType(ft) {<br />
cout<<"Shape Construct"<<endl;<br />
};<br />
char *getType() {return figType;};<br />
virtual double Area() {return 0.0;};
};<br />
<br />
class Square:public Shape {<br />
protected:<br />
double length;<br />
public:<br />
Square(double l):Shape("Square") {<br />
length = l;<br />
cout<<"A Rectangle Object Created"<<endl;<br />
};<br />
double Area() {return length*length;};<br />
};<br />
<br />
class Rectangle:public Shape {<br />
protected:<br />
double height, width;<br />
public:<br />
Rectangle(double h, double w):Shape("Rectangle") {<br />
height = h;<br />
width = w;<br />
cout<<"A Rectangle Object Created"<<endl;<br />
};<br />
double Area() {return height*width;};<br />
};<br />
<br />
class Triangle:public Shape {<br />
protected:<br />
double height, base;<br />
public:<br />
Triangle(double h, double b):Shape("Triangle") {<br />
height = h;<br />
base = b;<br />
cout<<"A Triangle Object Created"<<endl;<br />
};<br />
double Area() {return height*base;};<br />
};<br />
<br />
class Circle:public Shape {<br />
protected:<br />
double pir;<br />
public:<br />
Circle(double p):Shape("Circle") {<br />
pir = p;<br />
cout<<"A Circle Object Created"<<endl;<br />
};<br />
double Area() {return pir*pir;};<br />
};<br />
<br />
void main() {<br />
Shape *s1;<br />
Rectangle *rp1;<br />
Rectangle r1(3,5);<br />
<br />
s1=&r1;
rp1=&r1;
<br />
cout<<"Area() applied through Rectangle pointer "<<rp1->Area()<<endl;<br />
cout<<"Area() applied through Shape pointer "<<s1->Area()<<endl;<br />
};<br />
All I want to know right now is, how similar is the code to the question asked above ? Can I apply this structure for using OpenGL instead of using characters for drawing the objects ? And where can I get nice and easy examples ?
Thanks in advance
Tolga
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I have a list control and a number of handlers. What I want is to be able to process key presses as well as mouse clicks so if I select an item and press the Delete key on the keyboard I can call my Delete button handler. I have a handler called OnKeydownMyList() which is called when I press a key. How do I find out what key has been pressed so I can call the right handler?
Thank you.
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Hi,
Your OnKeyDownMyList() looks like this :
<br />
void Cxxx::OnKeyDownMyList( NMHDR* pNMHDR, LRESULT* pResult )<br />
{<br />
LV_KEYDOWN* pLVKeyDow = ( LV_KEYDOWN* ) pNMHDR;<br />
<br />
<br />
*pResult = 0;<br />
}<br />
Here you can use the wVKey member of the pLVKeyDow..
Example :
<br />
void Cxxx::OnKeyDownMyList( NMHDR* pNMHDR, LRESULT* pResult )<br />
{<br />
LV_KEYDOWN* pLVKeyDow = ( LV_KEYDOWN* ) pNMHDR;<br />
<br />
if( pLVKeyDow->wVKey == VK_DELETE )<br />
{<br />
}<br />
<br />
*pResult = 0;<br />
}<br />
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Thank you. That is exactly what I wanted
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Hello everyone out there...
I need a help on MDI in MFC/VC++. I have managed to create three child windows when the application is run. But I am not able to create an interaction between the childwindows. Something like this..... when the user clicks a menu item, all the three child windows should get updated simultaneously with the click...or one by one when the user clicks on that particular child window....
Please mail me with the solution....
Thanks....
Regards...
Ruchit Sharma R
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Check whether following function works
CWnd::SendMessageToDescendants()
or objChildWind.SendMessage()
objChildWind.PostMessage()
greatest thing is to do wot others think you cant
suhredayan@omniquad.com
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Hello,
Is their any way find the correct attributes for the CFont class that make a specific font? Eg, what are the attributes for CFont for the font: New Times Roman size 20?
I'm finding it hard to get the correct font that I require by changing the attributes in CFont class.
Hope I explained this well enough.
Thanks in advance.
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Make a simple MFC Application
Do
CFontDialog dlg;
if(dlg.DoModal()== IDOK)
{
..
}
Hope it Helps
Live as if your were to die tomorrow. Learn as if you were to live forever.
-Mahatma Gandhi
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Yes it did. Thanks very much;)
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I need to make a progress control using GDI+ that can be added at runtime.
How would you go about implementing graphically the bar. Would you use a
rectange and keep inflating it? Any suggests would be appreciated.
Steve
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Hi,
I'm making an app with a static splitter and in one of the panes I have a control view. I would like to set the size of the control pane to match that of the dialog resource. I prefer to do it programatically if it's possible, so that it updates automatically whenever I change the dialog.
I know how to set the sizes in the splitter with SetColumnInfo, so I just need a way to get the correct size from the resource.
thanks
Ludde
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Use this code in your CDialog derived class (class associated with your dialog resource)
<br />
CRect rect;<br />
GetWindowRect(&rect);<br />
hope that helps
Muhammad Shoaib Khan
http://geocities.com/lansolution
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I did some searching as i once read such a problem and the solution as well
Lucky You I found it
Below is an Excerpt from C++Q&A (SEPEMBER 1998) by Paul Dilascia
Hope it Helps 
A) This is a typical Windows chicken-and-egg problem, one of those things that seems like it should be easy but isn't. One way to find the size of a dialog is to load the dialog resource into memory—that is, into a DLGTEMPLATE structure—and look at the cx/cy parameters. Unfortunately, these values are in dialog base units, not pixels. So you have to call GetDialogBaseUnits and do some coordinate conversions, which depend on whether your dialog uses the system font or its own font.
Fortunately, there's an easy and surefire way to find out the size of a dialog, even if it is a bit kludgy: just create the dialog, and see how big it is! Of course, you have to create it invisibly if you don't want the user to see what you're doing. But the dialog used for a form-based app is invisible by default, so in this case making the dialog invisible doesn't require extra effort.
To see how it works, I added the automatic sizing feature to the FormSwap program mentioned in the answer to the previous question. The core of the autosize feature is a static function, GetDialogSize, which gets the size of the form. Yes, even in the days of C++, I still write static functions from time to time. But GetDialogSize is implemented using a C++ class, CTempDlg:
class CTempDlg : public CDialog {
public:
CRect m_rcDlg;
protected:
virtual BOOL OnInitDialog();
};
BOOL CTempDlg::OnInitDialog()
{
GetWindowRect(&m_rcDlg);
m_rcDlg -= m_rcDlg.TopLeft();
EndDialog(0);
return TRUE;
}
CTempDlg has just one function override: OnInitDialog. OnInitDialog saves the position of the dialog in a data member, then quits. (MFC does a bit of trickery to allow this; in straight C you can't call EndDialog from within WM_INITDIALOG.) GetDialogSize uses CTempDlg to get the dialog's size, which it returns as a CSize.
CSize GetDialogSize(LPCTSTR pszTemplName,
CWnd* pParent)
{
CTempDlg dlg;
dlg.Create(pszTemplName, pParent);
return dlg.m_rcDlg.Size();
}
Pretty simple. If you try this at home, just remember that the dialog should have no borders and should be invisible (dialogs used in form views always are).
If you want to get the size of a normal dialog, you'll have to do a bit more coding. To first load the dialog template into memory, turn off the WS_VISIBLE and WS_BORDER styles in the DLGTEMPLATE structure and call CDialog:: CreateIndirect instead of Create. If you're already loading the dialog into memory, you may as well just convert the cx and cy values using GetDialogBaseUnits. In passing, I should also mention another function, MapDialogRect, that converts dialog box units to screen pixels. However, this function requires an HDLG, which is an already created dialog.
Once you have the size of the dialog, you've solved the main problem of sizing your frame—but you aren't out of the woods yet. Now the problem is: given that you know how big the dialog is (that is, how big the client view area should be), how big must you create your main window to get a client area exactly that size? This sounds simple but it turns out to be a real pain in the keyboard. There's a virtual function, CWnd::CalcWindowRect, that's supposed to accomplish this feat. Given a certain-sized client rectangle, it calculates the corresponding frame rectangle. Unfortunately, no one in Redmond bothered to implement this function for CFrameWnd. So that leaves it to you.
Implementing CalcWindowRect is an exercise in nit-picking, or should I say pixel-picking. Given a certain-sized client rectangle, you have to add the heights and widths of all the toolbars, splitter borders, menus, window frames, and what-have-you. In the case of FormSwap, there are toolbars, the splitter window, and the left-pane view that must be taken into account. To calculate the height of the toolbars, you can use the MFC function CWnd::RepositionBars. You feed it a rectangle and a magic code, reposQuery—which says you only want to calculate the toolbars, not actually move them—and presto, you have the numbers you need. If you want to understand RepositionBars better, read the documentation. Good luck.
After calculating the heights of the toolbars, the next troublesome task is calculating the height and width of all the splitter window components: the border with which it surrounds each pane and the splitter bar itself. All these magic numbers are contained within data members in CSplitterWnd, but naturally the data is protected, which means you can't access it! Sigh. So what do you do? Simple: just derive a new class with public functions to export the protected data, and use it instead of CSplitterWnd in your main frame.
class CMySplitterWnd : public CSplitterWnd {
public:
CSize GetBorderSize()
{ return CSize(m_cxBorder,m_cyBorder); }
CSize GetSplitterSize()
{ return CSize(m_cxSplitter,m_cySplitter); }
};
If you're lazy (the best programmers are), you might be tempted to just hardwire the border size and other measurements instead of going to all this trouble. But be warned: the values m_cyBorder and its sisters are different under Windows 3.1, Windows 95, and Windows NT®. So if you want the exact values, you must get them from an instantiated CSplitterWnd object.
By now you've probably fallen asleep just thinking of all this tedious work, but once you've calculated how big your main frame should be, the next step is to actually modify the frame's size. Where do you do it? There are oh, so many places. You could override PreCreateWindow and set the size in CREATESTRUCT, implement a WM_GETMINMAXINFO handler, or alter the size in CFrameWnd::OnCreate. In this particular case, however, there's only one option because the magic RepositionBars function works only after the toolbars have been created. This means the winner is door number three: OnCreate.
int CMainFrame::OnCreate(...)
{
•
•
•
static CSize sz = GetDialogSize(MAKE
INTRESOURCE(IDD_DIALOG1), this);
CRect rc(CPoint(0,0), sz);
CalcWindowRect(&rc);
SetWindowPos(NULL, 0, 0,rc.Width(), rc.Height(),
SWP_NOMOVE|SWP_NOZORDER);
return 0;
}
With this and all the other code in place, the window now appears as in Figure 1, just large enough to enclose the form, and not one pixel larger. Whew!
Before signing off, let me spend a few words on WM_GETMINMAXINFO. Windows sends this message just before creating a window, and again whenever the user attempts to move or size it. WM_GETMINMAXINFO is your opportunity to specify the minimum and maximum sizes allowed for your window. If, after going to all that trouble to calculate the window size, you want to prevent the user from decreasing the size of the window, you should handle WM_GETMINMAXINFO. Just follow the directions in your Win32® Owner's Manual. Don't forget that Windows sends the first WM_GETMINMAXINFO before it creates your window, so RepositionBars won't work. You either have to implement CalcWindowRect another way, without using RepositionBars, or ignore the first WM_GETMINMAXINFO message. One way to do this would be to make the dialog size a data member, m_szDlg, which you initialize to zero and then set in OnCreate. Then your WM_GETMINMAXINFO handler would do nothing if m_szDlg is zero.
Live as if your were to die tomorrow. Learn as if you were to live forever.
-Mahatma Gandhi
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Thank you very much!! I haven't had time to dig through all of it yet, but it sure looks promising.
thanks again!
/Ludde
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Hi,
can anyone tell me whether I can send SMS programatically. If yes, are there any references / net-links where I can get some more info.
thanks
Partho
"It was when I found out I could make mistakes that I knew I was on to something."
-Ornette Coleman
"Philosophy is a study that lets us be unhappy more intelligently."
-Anon.
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You can send SMS via MAPI. You can find a sample program on web for the same.
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Thanks,
Can I use MAPI for all mobile phone services?
"It was when I found out I could make mistakes that I knew I was on to something."
-Ornette Coleman
"Philosophy is a study that lets us be unhappy more intelligently."
-Anon.
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How do I get my IP address while I am on line. I used function gethostbyname( ) and from there I used function inet_ntoa( ) to get IP address. But this IP address appears to be static. I mean it does not change whether I am on line or off line, and even after I restart my PC it is always the same.
Thanks,
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Anonymous wrote:
I mean it does not change whether I am on line or off line, and even after I restart my PC it is always the same.
It might be. Mine is. If your PC doesn't rely on BOOTP or DHCP for configuration, you have a static address.
"Another day done - All targets met; all systems fully operational; all customers satisfied; all staff keen and well motivated; all pigs fed and ready to fly" - Jennie A.
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If you are using dialup you can try with GetProjectionInfo() and RasEnumConnections(). Check MSDN to know more about these funtions
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Hello,
We have a windows app that can be started in a 'test mode'. In this mode the main window is hidden and another testing dialog is shown. The testing dialog does not have a parent window.
This is an MFC app and VWinApp->m_pMainWnd always points to the hidden main window, not the testing dialog.
When run in this test mode there is no icon on the task bar for the app. How can I make an icon appear in the task bar in this case.
Cheers
Josh
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From MSDN :
There are two ways to prevent a window from appearing on the shell's taskbar and in the task list window that appears when you press ALT+TAB.
Give the window the WS_EX_TOOLWINDOW extended style, and remove the WS_EX_APPWINDOW style. As a side effect, the window will have a smaller caption than a normal window.
Give the window the WS_POPUP style and make it owned by a hidden window.
If a window is created or shown such that it appears in the taskbar, then the window should be in the same state when it is destroyed or hidden. If the visibility on the taskbar is not synchronized, then the taskbar may end up with a blank button where it thinks the window should still appear.
Hope that helps
Live as if your were to die tomorrow. Learn as if you were to live forever.
-Mahatma Gandhi
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